Effects of type 1 diabetes mellitus on efferent auditory system in children and adolescents

Aim: To investigate whether type 1 diabetes mellitus (T1DM) could affect the efferent auditory system by analyzing the relationship between the activation of the medial olivocochlear reflex with disease duration, metabolic control and age at time of diagnosis.

Method: A total of 101 children and adolescents were evaluated. They were divided into two groups: 50 with T1DM and 51 without the disease. The participants answered a structured questionnaire containing questions about auditory complaints and were evaluated for tonal audiometry, tympanometry, acoustic reflex, otoacoustic emission by distortion product to evaluate the inhibitory effect of medial olivocochlear reflex (MOC).

Results: The participants with T1DM presented changed AR (increased or absent) at all the frequencies in both ears (p < 0.05) when compared with the group without the disease. No differences were found between the DPOAE amplitudes of the individuals with and without T1DM, in both ears at all the frequencies. There were significant differences in the activation of the MOC reflex between the groups with and without T1DM, the participants with T1DM presented the absence of the inhibitory effect of the DPOAE in the right and left ears, in the frequencies of 4000 Hz (p = 0.035/0.002respectively) and 6000 Hz (p = 0.033/0.031 respectively) and 8000 Hz (p = 0.007/0.001 respectively) when compared to the healthy group. Significant differences were also observed between the groups with and without T1DM (p < 0.05) for self-reported complaints of tinitus, difficulties with the perception of speech when there was noise and distraction with noise. No association was found between the hearing complaints and the audiological measurements obtained and disease time, metabolic control and age at the time of diagnosis.

Conclusion: The findings suggest the presence of early auditory dysfunction of the efferent pathway in patients with T1DM.